The invention relates to a device of the type for the coupling of lasers, diodes or the like with light-conducting fibers or of such fibers with on another.
Various arrangements are known for guiding the laser beam of a semiconductor laser into a monomode light wave guide. One arrangement consists of coupling a tapered end of a fiber with a lens soldered on directly with a laser diode. A second known device consists of coupling a fiber with the laser diode by means of a gradient lens (GRIN) and a spherical lens. Finally, one further arrangement consists of coupling the end of the fiber with the laser diode, by means of a connecting optical unit having two spherical lenses.
All of these devices have the disadvantage that they are difficult to adjust, since the active diameter of single-mode fibers is less than 10 pm. If the adjustment tolerances are still smaller, then the difficulties of adjustment increase correspondingly.
Adjustment apparatuses with mechanically redundant screw connection of the type as known per se are, in the submicrometer range, difficult to handle, and are furthermore too bulky for micro-technical applications. It is also known to adhere semi-conductor lasers and planar wave guides directly. Because of contractions during the hardening, the precise adjustments are lost again. Low-contraction adhesives have high proportions of filling materials, are thus very viscous, and are therefore scarely suited for binding small parts in the form of laser diodes, fibers and the like by means of adhesives, without disadvantages for the adjustment. Also, adhesive materials which polymerize under UV light, which can be applied before the adjustment, do not meet the very high demands placed as regards to the rigidity of the adhesive connection.
The task forming the basis of the invention is that of creating a device of the type concerned for the coupling of lasers, diodes or the like with light-conducting fibers, or of such fibers with one another, which makes possible an adjustment of the coupling with high precision, as well as a fixation by means of adhesive materials without having an influence on the adjustment.
The task which forms the basis of the invention is solved by means of the theory stated in the characterizing portion of claim 1.
The basic concept of the theory in accordance with the invention is that of creating precise sliding surfaces for the guide device both in the direction of the optical axis as well as in all directions perpendicular thereto as well, which, during corresponding fitting to one another, make possible not only a simple adjustment, but also maintain the selected adjustment position on the basis of friction forces between the contact surfaces, if the parts are connected with one another by means of adhesive materials after the adjustment. If a sufficiently water adhesive material is used, then, because of the capillary effect, the adhesive flows into the very narrow intermediary space between the surfaces fitting with one another, and is optimally distributed there. If adhesive material which hardens very rapidly is used, then the fixation of the adjustment point is achieved in only a few seconds.
The adjustment can naturally be carried out with the help of auxiliary devices which maintain the adjustment position for at least a short time. After the application of the adhesive material, the adjustment position is then fixed. The support parts holding the optical elements, such as laser, diode, fibers or the like, can thus be extremely small, and are suited for an automatic adjustment, and the fixing is also extremely sturdy. The optical elements which are to be coupled with one another can essentially be of any type desired. The device in accordance with the invention is always suitable in such a place where such optical elements have to be oriented, adjusted and fixed in the direction of one optical axis and in all directions perpendicular thereto.
According to the theory of claim 2, the sliding surfaces which form the axial guide device are partially cylindrical, and they thus form a telescope-like guide device. One such embodiment can be produced in a particularly simple and precise manufacturing process. In this, the question of which part the internal surfaces and the external surfaces are located on is entirely a matter of choice. It is suitable, however, that the sliding surface on the one support body is an external surface, and the sliding surface on the intermediary body is an internal surface. In order to provide accessibility to the contact area between the sliding surfaces, for the purpose of applying adhesive materials, it is suitable to provide. within the externally-positioned part, at least one opening up to the boundary surface.
The support body can have, for the mounting support of a light-conducting fiber, a boring or hole into which this fiber is inserted and then fixed in an entirely simple manner.
In accordance with one particularly suitable further development in accordance with claim 7, the support body for a laser has, in the direction of the optical axis, a hollow space in front of the laser for the mounting of optical elements, particularly of an interfermeter. Suitable in this connection is one further development of this embodiment, in accordance with which a second intermediary body is provided, which is coordinated with the other intermediary body and, in the same manner as the intermediary body coordinated with the first support body, is displaceable with respect to the other support body in the direction of the optical axis, whereby a mounting body is positioned between both intermediary bodies, which mounting body has two parallel contact surfaces, on which the contact surfaces of the intermediary body are fitted in a displaceable manner, and between which a hollow space for the accommodation of optical elements is located. Thus, on both sides of the optical device provided in the mounting body, an adjustment of a light-conducting fiber both in the direction of the optical axis as well as in all directions perpendicular thereto is thereby possible.
In all cases, it is appropriate that the distance between the optical elements to be coupled is as small as possible, in order to not disadvantageously allow dispersions to appear in the transition area between the optical elements, unless additional optical elements, such as, for example, lenses or the like, are provided for the prevention of these disadvantages.